A 38-year-old driver died after her vehicle ran off the road and overturned Thursday night in Conway, authorities said.

Carolyn L. Oliver of Conway was driving south on Arkansas 36 near Debbie Lane shortly before 10:30 p.m. when her 2002 BMW veered off the right side of the highway, crossed a ditch and overturned, Arkansas State Police said.

Oliver died from unspecified injuries.

It wasn't clear what caused the single-vehicle crash. Conditions at the time were described as clear and dry.

The death and three others Thursday raised to 221 the number of people killed in traffic crashes in Arkansas so far this year, according to preliminary figures.